The field of the invention is food machinery and the invention relates more particularly to food machinery of the type which forms a continuous sheet of a food preparation product such as dough or masa which is then cut to form raw chips which are cooked to provide consumer products such as corn chips or potato chips. One method of carrying out this process is shown in U.S. Pat. No. 5,571,549. In this structure, invented in part by the present applicant, one of the rollers is adjustable. This adjustment is provided by mounting the roller on a frame which is pivoted. A servo motor drive gear is sensitive to the space between two portions of the frame and adjusts the pressure between the two rollers accordingly. While such system is adequate for many purposes, there are some types of food products which are resistant enough to being sheeted that this structure does not provide sufficient force to provide a thin sheet of consistent thickness.
It is an object of the present invention to provide a food processing machine which includes an adjustable roller which is adjustable with such accuracy and supported with such strength as to provide a constant thickness of a sheeted product in spite of the difficulty in forming a sheeted product.
This invention is for an adjustable roller assembly for producing sheeted food products of an accurate thickness. The assembly includes an adjustable roller positionable adjacent a second roller. The assembly includes a frame which has two opposing roller support frame members. A first pair of opposed bearings is held by the roller support frame members and the first pair of opposed bearings have an aligned center along a first axis of rotation. A pair of turnable members are supported in the first pair of opposed bearings and these turnable members are moveable through at least an arc centered about the first axis of rotation. A second pair of opposed bearings is held by the turnable members and the second pair of opposed bearings support an adjustable roller about a second axis of rotation which is parallel to the first axis of rotation, but is offset from the first axis of rotation. Means are provided for rotating the adjustable roller about the second axis of rotation. Means are also provided for adjustably setting the polar orientation of the first pair of turnable members, thereby changing the center of rotation of the adjustable roller to provide an accurate end product thickness. Preferably, the turnable members are turned by the adjustable position of a pair of drive gears which move a driven gear attached to the turnable members. Also preferable, the turnable member at one end of the adjustable roller is independently adjustable from that at the other end. A process for continuously forming a thin sheet of uncooked food product of a uniform thickness in spite of variations of the rheology of the uncooked food product comprises the steps of continuously feeding a sheet of an uncooked food product in a dough-like form between the nip between two rollers. At least one of the two rollers is an adjustable roller which is mounted between a pair of bearings which is held eccentrically in a pair of turnable members supported by a frame. Means are provided for measuring the width of the nip between the rollers to provide a signal sensitive to the width of the nip. Means sensitive to this signal are used to set the rotational position of the turnable members, thereby causing the adjustable roller to be moved to correct for a change in the width of the nip, thereby providing a product of highly uniform thickness of sheeted uncooked product. The term xe2x80x9cuncookedxe2x80x9d is intended to mean not fully cooked and may include a product which has been partially cooked.